The following sections describe two techniques for interconnecting the input ports of microwave filters suitable for sorting signals into large numbers of contiguous frequency bands. Both techniques are capable of extension to very large numbers of channels, and both are believed to be new and useful. Both have been tested at microwave frequencies and give results in reasonable agreement with those predicted. One technique uses the impedance transforming property of a uniform transmission Iine to achieve the equivalent of the directional filter. It has proved especially valuable in the design of practical filters providing large numbers of channels in several microwave frequency bands. The other is based upon a width-tapered waveguide, which serves as a space-distributed high-pass filter.